Easing curves control how an action animates from its initial value to its final value. Mathematically speaking, easing curves control the rate of change of a property over time. Play offers Default, Linear, Ease In, Ease Out, Ease In & Out, Custom (Cubic Bezier), Spring, and Custom (Spring) easing.

The animation has constant speed for the full duration.

The animation starts slow and speed up at the end.

The animation starts fast and slows down at the end.

The animation starts slow, speeds up in the middle, and slows down again at the end.

This custom animation uses two coordinates (Point 1 X & Point 1 Y and Point 2 X & Point 2 Y) to specify the rate of change at a given moment in the animation. The X coordinates control timing, and the Y coordinates control progress.

For Point 1, higher X (more time) and lower Y (less progress) values mean a slower start to the animation.

For Point 2, lower X (more time, since it's measured from the end of the animation and higher Y (less progress) values mean a slower end to the animation.

Each coordinate should be between 0-1. You can try visually creating cubic bezier curves with this website.

The animation bounces according to the Spring Intensity:

The animation bounces according to the Damping value at a given speed: